This article presents a novel hybrid electronic-photonic interconnection for terahertz on-chip communications. The silicon waveguide-based interconnect features the integration of a uni-traveling-carrier photodiode as a transmitter and a resonant tunneling diode as a receiver. The interconnect achieves low transmission loss spanning the WR-2.8 band from 260-390 GHz. On-chip communications with data rates up to 100 Gb/s at 315 GHz are demonstrated with high coupling efficiency through precise waveguide alignment, and superior bit error rate performance. Terahertz on-chip interconnections have great potential for 6G communications backhaul, AI and massive internet of things applications.